# Copyright (C) 2017 Beijing Didi Infinity Technology and Development Co.,Ltd.
# All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================
"""Hooks"""

import tensorflow as tf


class DatasetInitializerHook(tf.train.SessionRunHook):
  ''' iterator dataset initailizer '''

  def __init__(self, iterator, init_feed_dict):
    self._iterator = iterator
    self._init_feed_dict = init_feed_dict

  def begin(self):
    self._initializer = self._iterator.initializer

  def after_create_session(self, session, coord):
    del coord
    session.run(self._initializer, self._init_feed_dict)
